The Brewer’s sparrow is our smallest sparrow. It is long-tailed,
slim and small-billed. Its plumage is subtle and undistinguished
with weak facial contrast.

Two species are generally recognized, S. b. breweri and the
‘Timberline’ sparrow, S. b. taverneri. Each has different breeding
ranges, which may overlap, and have subtle plumage differences. The
breeding ranges are eastern Alaska, Yukon, central south B.C., east
to southeast Saskatchewan, south to New Mexico, Arizona and south
central California. It is absent from the coastal pacific areas and
winters in southwest U.S. and northern Mexico.

Identification:

General: The head is very subtlety streaked. The supercilium
is pale dull gray to dull whitish. The eye is dark with a white eye
ring. Moustachial and malar stripes are thin and brown. The bill is
small, conical, pale brown with dusky tip. Nape and mantle streaked.
The rump is brown with dark brown streaks. Wings are brown with
poorly defined wing bars. Tail is long, notched and brown.
Underparts are pale and unstreaked, breast and flanks dingy gray,
sometimes lightly streaked under the wings. The belly is dull white,
legs and feet are pale pink or pale horn colour. Length: 12-13cm.
Weight: 10.5g.

Adult Male: No distinguishing differences between male and
female.

Adult Female: No distinguishing differences between male and
female.

Juvenile: Similar to adults but less streaked above with
breast and flanks narrowly streaked with black triangular markings.

Similar Species: Clay-colored Sparrow is similar but Brewer’s
is plainer, drabber with less contrasting nape and more conspicuous
white eye ring. Chipping Sparrow has a rusty cap during breeding, a
white supercilium and black eye stripe. Clay-colored and Chipping
are similar in size and shape.

Behaviour: Quite inconspicuous on the breeding ground where
most activities take place undercover of vegetation. Hops on ground;
occasionally runs. Hops or clambers about among twigs and branches
within shrubs. Main foods taken are small insects, mainly gleaned
from foliage and bark of shrubs or dwarf trees; also seeds usually
taken from ground. Although its bill morphology is typical for a
sparrow, much of this species’ diet consists of arthropods. As
benefits an arid land species, its water economy is excellent and
can exist for long periods without drinking.

Habitat: Breeds in a variety of habitats, but in the southern
parts of their range they prefer big sagebrush and silverberry in
short grass. The northern population is found in subalpine fir and
krummholz. Winters in loose flocks in arid brushy areas with patches
of grass.

Information:

John Cassin named this sparrow in 1856 in honor of his friend,
Thomas M. Brewer.

Shortly after arrival on the breeding grounds Brewer’s pairs build a
small open-cup nest in sagebrush and lay 3 bluish-green marked with
brown, eggs.

Conservation:

Numbers have dropped by about 60% since 1961; the reasons for this
are unclear, but reflect habitat destruction.

Capture Rates

Brewer’s Sparrow breeds in the landscape of the
intermountain west dominated by sagebrush. Therefore, it is
vagrant visitor to Colony Farms as is reflected by the low
capture rate in June and zero capture rate for the remainder
of the year. Capture rates are standardized as birds
captured per 100 net hours from 2010 - 2012.